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author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2012-12-12 00:01:03 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-12 01:22:23 (GMT) |
commit | d9713679dbd2a6ecb840cd5b65a3ec555c1ec3d4 (patch) | |
tree | b998ae43dc18e7459cab5a2cb5ba12900c96c7e1 /mm/memory_hotplug.c | |
parent | 6dcd73d7011ba9046f9b98e7f7c9d958f5810e6b (diff) | |
download | linux-d9713679dbd2a6ecb840cd5b65a3ec555c1ec3d4.tar.xz |
memory_hotplug: fix possible incorrect node_states[N_NORMAL_MEMORY]
Currently memory_hotplug only manages the node_states[N_HIGH_MEMORY], it
forgets to manage node_states[N_NORMAL_MEMORY]. This may cause
node_states[N_NORMAL_MEMORY] to become incorrect.
Example, if a node is empty before online, and we online a memory which is
in ZONE_NORMAL. And after online, node_states[N_HIGH_MEMORY] is correct,
but node_states[N_NORMAL_MEMORY] is incorrect, the online code doesn't set
the new online node to node_states[N_NORMAL_MEMORY].
The same thing will happen when offlining (the offline code doesn't clear
the node from node_states[N_NORMAL_MEMORY] when needed). Some memory
managment code depends node_states[N_NORMAL_MEMORY], so we have to fix up
the node_states[N_NORMAL_MEMORY].
We add node_states_check_changes_online() and
node_states_check_changes_offline() to detect whether
node_states[N_HIGH_MEMORY] and node_states[N_NORMAL_MEMORY] are changed
while hotpluging.
Also add @status_change_nid_normal to struct memory_notify, thus the
memory hotplug callbacks know whether the node_states[N_NORMAL_MEMORY] are
changed. (We can add a @flags and reuse @status_change_nid instead of
introducing @status_change_nid_normal, but it will add much more
complexity in memory hotplug callback in every subsystem. So introducing
@status_change_nid_normal is better and it doesn't change the sematics of
@status_change_nid)
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Rob Landley <rob@landley.net>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r-- | mm/memory_hotplug.c | 136 |
1 files changed, 120 insertions, 16 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index ec2f199..7219560 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -460,6 +460,53 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, return 0; } +/* check which state of node_states will be changed when online memory */ +static void node_states_check_changes_online(unsigned long nr_pages, + struct zone *zone, struct memory_notify *arg) +{ + int nid = zone_to_nid(zone); + enum zone_type zone_last = ZONE_NORMAL; + + /* + * If we have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_NORMAL, set zone_last to ZONE_NORMAL. + * + * If we don't have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. + */ + if (N_HIGH_MEMORY == N_NORMAL_MEMORY) + zone_last = ZONE_MOVABLE; + + /* + * if the memory to be online is in a zone of 0...zone_last, and + * the zones of 0...zone_last don't have memory before online, we will + * need to set the node to node_states[N_NORMAL_MEMORY] after + * the memory is online. + */ + if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY)) + arg->status_change_nid_normal = nid; + else + arg->status_change_nid_normal = -1; + + /* + * if the node don't have memory befor online, we will need to + * set the node to node_states[N_HIGH_MEMORY] after the memory + * is online. + */ + if (!node_state(nid, N_HIGH_MEMORY)) + arg->status_change_nid = nid; + else + arg->status_change_nid = -1; +} + +static void node_states_set_node(int node, struct memory_notify *arg) +{ + if (arg->status_change_nid_normal >= 0) + node_set_state(node, N_NORMAL_MEMORY); + + node_set_state(node, N_HIGH_MEMORY); +} + int __ref online_pages(unsigned long pfn, unsigned long nr_pages) { @@ -471,13 +518,18 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) struct memory_notify arg; lock_memory_hotplug(); + /* + * This doesn't need a lock to do pfn_to_page(). + * The section can't be removed here because of the + * memory_block->state_mutex. + */ + zone = page_zone(pfn_to_page(pfn)); + arg.start_pfn = pfn; arg.nr_pages = nr_pages; - arg.status_change_nid = -1; + node_states_check_changes_online(nr_pages, zone, &arg); nid = page_to_nid(pfn_to_page(pfn)); - if (node_present_pages(nid) == 0) - arg.status_change_nid = nid; ret = memory_notify(MEM_GOING_ONLINE, &arg); ret = notifier_to_errno(ret); @@ -487,12 +539,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) return ret; } /* - * This doesn't need a lock to do pfn_to_page(). - * The section can't be removed here because of the - * memory_block->state_mutex. - */ - zone = page_zone(pfn_to_page(pfn)); - /* * If this zone is not populated, then it is not in zonelist. * This means the page allocator ignores this zone. * So, zonelist must be updated after online. @@ -521,7 +567,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; if (onlined_pages) { - node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); + node_states_set_node(zone_to_nid(zone), &arg); if (need_zonelists_rebuild) build_all_zonelists(NULL, NULL); else @@ -871,6 +917,67 @@ check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) return offlined; } +/* check which state of node_states will be changed when offline memory */ +static void node_states_check_changes_offline(unsigned long nr_pages, + struct zone *zone, struct memory_notify *arg) +{ + struct pglist_data *pgdat = zone->zone_pgdat; + unsigned long present_pages = 0; + enum zone_type zt, zone_last = ZONE_NORMAL; + + /* + * If we have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_NORMAL, set zone_last to ZONE_NORMAL. + * + * If we don't have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. + */ + if (N_HIGH_MEMORY == N_NORMAL_MEMORY) + zone_last = ZONE_MOVABLE; + + /* + * check whether node_states[N_NORMAL_MEMORY] will be changed. + * If the memory to be offline is in a zone of 0...zone_last, + * and it is the last present memory, 0...zone_last will + * become empty after offline , thus we can determind we will + * need to clear the node from node_states[N_NORMAL_MEMORY]. + */ + for (zt = 0; zt <= zone_last; zt++) + present_pages += pgdat->node_zones[zt].present_pages; + if (zone_idx(zone) <= zone_last && nr_pages >= present_pages) + arg->status_change_nid_normal = zone_to_nid(zone); + else + arg->status_change_nid_normal = -1; + + /* + * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE + */ + zone_last = ZONE_MOVABLE; + + /* + * check whether node_states[N_HIGH_MEMORY] will be changed + * If we try to offline the last present @nr_pages from the node, + * we can determind we will need to clear the node from + * node_states[N_HIGH_MEMORY]. + */ + for (; zt <= zone_last; zt++) + present_pages += pgdat->node_zones[zt].present_pages; + if (nr_pages >= present_pages) + arg->status_change_nid = zone_to_nid(zone); + else + arg->status_change_nid = -1; +} + +static void node_states_clear_node(int node, struct memory_notify *arg) +{ + if (arg->status_change_nid_normal >= 0) + node_clear_state(node, N_NORMAL_MEMORY); + + if ((N_HIGH_MEMORY != N_NORMAL_MEMORY) && + (arg->status_change_nid >= 0)) + node_clear_state(node, N_HIGH_MEMORY); +} + static int __ref __offline_pages(unsigned long start_pfn, unsigned long end_pfn, unsigned long timeout) { @@ -905,9 +1012,7 @@ static int __ref __offline_pages(unsigned long start_pfn, arg.start_pfn = start_pfn; arg.nr_pages = nr_pages; - arg.status_change_nid = -1; - if (nr_pages >= node_present_pages(node)) - arg.status_change_nid = node; + node_states_check_changes_offline(nr_pages, zone, &arg); ret = memory_notify(MEM_GOING_OFFLINE, &arg); ret = notifier_to_errno(ret); @@ -980,10 +1085,9 @@ repeat: } else zone_pcp_update(zone); - if (!node_present_pages(node)) { - node_clear_state(node, N_HIGH_MEMORY); + node_states_clear_node(node, &arg); + if (arg.status_change_nid >= 0) kswapd_stop(node); - } vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); |